A lot of recipes (not just the incredible ones here!) include the step of boiling sweetened condensed milk in the can as a way to caramelize it. I think that people assume the only danger is in the can exploding if you don't keep it covered with boiling water.
There's actually another concern that is more serious. Although lead solder is (legally) no longer allowed in making cans, there is still always some sort of sealant closing the seams of the can. Heating this sealant to the boiling point can cause the chemicals to leach into the liquid.
So instead, heat the SCM in a double-boiler for 1 1/2 hours, stirring occasionally. Still gets the job done (even slightly quicker!) and you don't have to worry about what's leaching into the caramel.
Edited for Angelique: Either way, covered or not. It can be easier to remember to stir if it's uncovered, but it also needs to be stirred more when it's uncovered (the surface gets dry and tough otherwise). The important detail to remember is to check on the water in the bottom part to make sure THAT doesn't go dry.
Thanks Tammy. I'm assuming the double boiler needs to be UNcovered?
ReplyDeleteThanks Tammy. I'm wondering if covering the mixture in the double boiler would cause too much steam/water to make the mixture runny? At least it does with chocolate.
ReplyDeleteMy mom melts chocolate in glass mason jars sitting in water in her electric skillet.
ReplyDeleteBut that's usually only when she's doing candy molds and need the chocolate to stay pliable for a long time.